The ultrasonic probe can be realized electricity harmonies which can the mutual conversion of the Q and ultrasonic wave propagation in elastic media, the physical characteristic is the basis of the seamless steel pipe principle of the ultrasonic flaw detection. Directional transmission of the ultrasonic beam propagation in Seamless encounter defects, and produces both a reflection of the wave generated wave attenuation. After the flaw detector of the signal processing, such as obtained using a reflection method flaw defect echo signals, such as penetration method flaw virtue through the degree of attenuation of the wave guide to the defect signal. Both can be a quantitative defect indication is given by the instrument.
The use of the piezoelectric effect or the electromagnetic induction principle different types of ultrasonic wave can be excited within the tube. Therefore, the piezoelectric ultrasonic and electromagnetic ultrasound can be used to pipe ultrasonic inspection. But the electromagnetic ultrasonic applies only to the ferromagnetic material.
Ultrasonic inspection of seamless pipes method
1, wave (or plate waves) reflection method the (or penetration method), in the state where the relative movement of the probe and a high pressure boiler tubes automatic inspection, the only special large-diameter seamless cam manual inspection. Automatic or manual inspection should ensure the sound beam scanning the surface of all of seamless steel pipe.
2, longitudinal defect inspection acoustic beam in the tube wall along the circumferential direction of propagation; test transverse defects propagation direction of the acoustic beam in the tube wall along the tube axis. The longitudinal and transverse defect inspection should be carried out in two opposite directions on the tube.
3,In demand-side transverse defect inspection is not made for the party inspection of longitudinal imperfections. Both parties agree that the buyer and the seller, the inspection of longitudinal and transverse defects can be only in the direction of the tube.
4,Automatic or manual inspection should be chosen coupled to good effect and without prejudice to the seamless steel pipe surface coupling medium.